A gate driver circuit in a display in operation needs to be controlled to scan the from first row to the last row of a screen sequentially, but in a real application, typically only some picture, e.g., a clock, the amount of charges in a battery, etc., needs to be displayed in a part of the area on the screen in some operating mode, e.g., a standby or charging mode, so if the existing display still has the first row to the last row of the screen scanned sequentially in these operating modes, then power may be consumed unnecessarily.